Field
Embodiments of the present disclosure generally relate to methods for forming a thin film transistor (TFT), and more specifically to methods for forming a TFT having a metal oxide layer.
Description of the Related Art
Metal oxide semiconductors, such as zinc oxide (ZnO) and indium gallium zinc oxide (IGZO) are attractive for device fabrication due to their high carrier mobility, low processing temperatures, and optical transparency. TFTs made from metal oxide semiconductors (MO-TFTs) are particularly useful in active-matrix addressing schemes for optical displays. The low processing temperature of metal oxide semiconductors allows the formation of display backplanes on inexpensive plastic substrates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The transparency of oxide semiconductor TFTs leads to improved pixel apertures and brighter displays.
However, a metal oxide layer, such as a metal oxide channel layer, is susceptible to the formation of oxygen vacancies in the layer, and the formation of oxygen vacancies lead to unstable TFTs. In addition, the formation of oxygen vacancies also causes a negative threshold voltage, since oxygen vacancies are donors in metal oxide materials.
Therefore, there is a need in the art for forming stable metal oxide TFTs.